With the rapid development of Chinese economy and construction as well as the initial formation of the economic globalization pattern, the logistics industry has been developed rapidly, and the requirement for container becomes greater increasingly. The tank container is one type of containers, and is widely used for containing and conveying various goods in liquid state, gaseous state and granular-powder solid state.
The tank container mainly consists of a frame and a tank body disposed inside the frame. The tank body includes a receptacle for holding goods, a pipe line and attaching pieces provided for preventing the goods from flowing. The frame generally includes a bottom frame, an end frame and force bearing elements, and is used for carrying various dynamic and static loads generated in the use of the container. The volume of the tank body is one of the important parameters which determine the load-carrying capacity of the tank container; and the reliability of the welding portion of the tank body provides an important guarantee for the safe use of the tank container.
For a long period of time, the tank container mainly adopts an elongate cylindrical tank body with a cross section thereof being processed to be circular, in which a end enclosure is usually a standard end enclosure in accordance with the Chinese Standard. The tank body of the container has been widely used due to relatively good force-bearing effect and relatively strong load-carrying ability resulting from its circular cross section. However, with the limitation of the external frame, there is a maximum threshold in the diameter of the circular cross section, that is, there is a maximum threshold in the volume, so that the load-carrying ability of the container can not be utilized completely. Thus, it is impossible that the volume of this elongate cylindrical tank body is further increased.
At present, to solve the above problem, the volume of the tank container is mainly increased by assembling and welding a plurality of steel plates and beam pieces into a non-circular tank body. By this way, the boundary of the frame of the container may be relatively effectively used. However, since this structure has relatively low load-carrying ability, reinforcement measures, e.g., providing a plurality of ribs inside the tank body, have to be taken to resist against the internal and external pressure imparted on the tank body in working, so as to improve the load-carrying ability of the structure. As a result, the dead weight of the tank body is increased, and the carrying capacity of the tank container is restrained. Furthermore, there are many welding seams on the tank body, and some problems such as leakage are prone to occur at the welding seam in use, resulting in that the reliability of the working of the tank container is decreased.
In a word, it has become a problem to be solved by those skilled in the art to reduce the dead weight of the tank body and to increase the load-carrying ability and the reliability of the tank body in the case of ensuring the relatively large volume of the container tank.